Automobile heating system



March""'l1. 1941. H J, DE N, McCQLLUM 2,234,268

AUTOMOBILE HEATING SYSTEM Filed April 6, 1938 3 Sheets-Sheet 1 Henry e/V. MC60/Zum 5y 2W ,myzkewam Mach 1l, 1941.

H. J. DE N. MCCOLLUM AUTOMOBILE HEATING SYSTEM Filed April, 6, 1938 3 Sheets-Sheet 2 March 11, 1941. H DE N. WCQLLUM 2,234,268

AUTOMOBILE HEATING SYS TEM Filed April 6, 1938 3 Sheets-Sheet 3 J0 21 61.105250 .bz?

Patented Mar. 1l, 1941 UNITED STATES PATENT GFFICE AUTOMOBILE HEATING SYSTEM Henry J. De-N. McCollum, Evanston, Ill.

Application April 6, `1938, Serial No. 200,318

5 Claims. v (Cl. 237-28) ment of the automobile, but even with the use of two heaters in an automobile, it is difficult to maintain the temperature substantially uniform throughout the compartment. Due to convection of the warm air produced by the heater, there isl a pronounced tendency for .the heated air to collect beneath the top. This tendency toward a pronounced temperature differential between the upper part of the compartment and the space adjacent the floor below is aggravated by the fact vthat; lthe floor is usually less well insulated than the top. The comfort of the passengers is dependent primarily upon lthe temperature of the air adjacent the oor, since, if the passengers feet are' maintained comfortably warm, he will justifiably consider the automobile to be adequately heated.

With the present :types of heater installations in automobiles, the passengers head is in a region of high temperature, while his feet are in a much cooler region. The temperature differential between the space adjacent the floor and that adjacent the :top of the passenger compartment may be as much as 20 F. or 30 F. This differential of temperature in the`rear portion of the sedan type automobile is greater lthan that in the portion in front of the front seat because in many automobile heaters the heater is provided with a fan which forces the air downwardly toward the floor. If the heater is of the type in which the heated air is forced horizontally by the fan, there may be a very decided temperature differential lbetween the region adjacent the top and the region adjacent the floor in front of the front seat of the vehicle, as well as in the space `behind the vfront seat.

' In accordance with my invention, I provide a means for withdrawing the cold air in the rgion adjacent .the floor behind the front seat, and forcing this cold airr upwardly, displacing the heated air adjacent the ltop of the compartment so las to cause -circulation of the air in directions opposite to the normal convection currents. By this method, the heated air is forced downwardly into the space between :the front and rear seats, and the passengers seated ln the rear seat are thus made more comfortable. To 5 raise the temperature of the space between the front and rear seats near the floor to the same temperature as Ithe top is practically impossible when using a customary automobile heating systein, because even if an extremely effective heater 10 were used, it would raise the temperature of .the space adjacent the top of the vehicle to such high temperature as to make lthe passengers uncomfortable -before the temperature adjacent the floor was raised appreciably. By maintaining the temperature more uniform throughout the whole compartment, I have discovered that it is not necessary to supply as much heat as would otherwise be necessary.` This is due not only to the fact that the temperature required for comfort is lowered if .the temperature is uniformly maintained throughout the compartment, but also because of the fact that when some portions of the compartment are at much higher temperature than others, the rate 'at which heat is conducted and radiated from the compartment is greater. This arises from the fast that the rate of dissipation of heat from a hotter body to a colder body varies as la power function of the temperature difference between the bodies, and not Ias a direct proportion.

It is lthus a primary object of my invention to provide anvimproved heating system for automotive Vehicles in which the temperature is maintained substantially uniformly throughout the passenger compartment.

A further object is to providevan improved heating system for sedan .type vehicles in which an improved method for heating the space between the front and rear seats is provided.

Other objects will appear from the following description, reference being had to' 'the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional view of a passenger compartment Aof a vehicle. showing 45 one form of the'apparatus provided for carrying out my improved method of heating;

Fig. 2 is a circuit diagram showing the connectionsfor supplying the'blower with electrical power.

Fig. 3 is a view similar to Fig. l showing a modified form ofpapparatus, wherein the blower is arranged for factory installation; 5-

Fig. 4 is a view similar to Fig. 1 showing a modied form of blower installatiom' 55.

its4

' 35I tion thereby.

fthe une s-s or nig. and l Fi 7 is a fragmentary sectional view taken on g of the front seat, although ordinarily such construction will be unnecessary if the air discharged from the blower is ejected at suillciently high vethe line 1-1 oi.Fig..6. The portion of an automobile shown in Fig. 1

comprises a iioor Ill usually ot metal, a 'metal top l0. I2,'and'a dash il, l5. The compartment is supplied with heat by a heater I8 secured to the dashi4. This heater may be o'f any well known type, 1 but is preferably one in which the heated air is forced downwardly from the. heater, as shown in loi my copending application Serial No. 61,213, tiled 1 January`28, 1,936. 'I'he approximate directions of the currents of heated air from theheater vare i indicated byfull linearrows, and show that although the heated air is initially directed down- 20 wardly by the heater fan, lt 'rapidly rises and g tends to collect directly beneath the top of the ve a different direction than the air currents nearer the center of the compartment. Generally, howr soi ever, the heated air will ilow*upwardly.as indicated 1 in Fig. 1 in the centrall portio'nofthe comparte ment and ilow` downwardly after being -in contact with the side walls and being cooled, and thus return to the heater for reheating and recircula- In accordance with the method Aot my inven- 1 tien, I provide a blower 20 just behind the of the irontgeat having its discharge nozzle directed upwardly along 'the back of the front seat-` 401 so that the current for4 air produced thereby will not be -directed against the bodies' of the per-v i sons seatedinv the rear seat. -The.- blower 2011s l' preferably electric motor operated andfis illus# vtrated in Fig. l astbeing supplied with current 4g;` through a conductor 22connecte'd to a suitable switch 24 mountedion the steering column 26.

Ifdesired, the connection io'r supplying the blow',-

i er motor with electric power maybe as shownl in Fig. 2,' wherein current from thebattery 28 is 50`- supplied to ignition switch 30 and thence through;

the switch 24 to one terminal of the motor for i the blowerf20, the. other terminal of the motor being groundedin the usualtmanner.

The. mower zo is directive to withdraw the'oold a-irj which tends to, collectfin the space 2l adja- I cent thetloor between the front andrear seats,

` and to eject/this cold air upwardly as indicated y by the'dotted arrows. This relatively cool air f is thus directed. against the top o't theeomparti o ment. where it is.` mixed 'with the warmer air g derived from the heater.. As a'result, the warmer l air which would otherwise tend to collect. beneath t. the top oi" the compartmentv isforced down'-` wardly lasindicated .by the' full line arrows, and

llr'the space.; between the iront and rear, seats is rendered substantially uniform in l tempe ature. The passengers in the rear. seat may thus made as comfortable 'as those in the iront seat, withj out the necessity of providing an additional heat- Fig. s is a. longitudinal sectional View taken on' -strict the foot room for :the passengers seated 4in'the rear seat. l v- ,-The'means for circulating the air-,that is the thelatter isadjusted. A vtapering groove may Ybe provided in the rear surface or the back ot the iront seat to yform a channel for the cold. airtdischarged from the blower 201- It desired, this groove 4or channel 34 may be closed to forma o conduit* extending to'the upper edge ofthe back locity to maintain -its cohesion as a separate stream. of air. In other respects, the construce tion and operation of the structure shown in Fig. 'l 3 is identical with that shown in Fig. l, and simi' lar reference characters halve therefore beenapplied to corresponding parts. l f -lo .In Fig. 4, I have shown a modified construction in which an electric motor 36 is `mounted upon the floorbetween the i'ront andrear seats .and drives a .Ian 38. The motortand the fan are enclosed in a housing III which may be of any `suitable decorativepcontour and which is provided` with a-.stream -directing outletnozzle 42. The casing 40 is provided. with a plurality' of inlet openings located close to the oor il so .that the cold1air which `otherwise tends vto 25 collect'adjacent the door will be drawn into "the housing and `ejected upwardly at relatively high velocity, as indicated by the dotted line arrows v'in Fig. 4, AWhile the motordriven fan.

-3'8 need not' eject the-air at such high velocity as' 20 vdoes the blower :n. the velooityotthe air should #be suillcient that the air -willilow-in a deiln'ite 4stream until it reaches substantially the top of the. vehicle. .Inl this way. the cold air will be effective to displace thewarmerair whichtends Il to collect immediately beneath the top ofthe and therefore to convey heat to the space2i. As 'av result, the vtemperature of the air in the 'space 2| will be edualized with that of the re-'m' maining air in the compartment, and the lpassengers seated 'in the rear seat lwill be made comfortable.

In Figs. 5, 46, and 7.,I'have shown a'further modiilcation of myinvention in which a blower is. utilized to draw air from the .space 2i 'adjacent the floor and eject itthrough a conduit to 1 a point beneath 'the top of the vehicle.' The blower is illustrated'as comprising a rotor 50,

mounted inahousing 521whichissecured to the' 50 door i0 of the vehicle. The 'cold air is ldrawn from'the space between the floor I0 and the rotor ,housing 52'and isej'ected through a conduit 54 which extends sidewardly to the sideedge of the .noor'and upwardly through the column 5B. 'I'he'lli` -cold air vdrawn-into theblc'wer is thusfejected' `through. the conduit il and dispersed nearthe top or the vehicle so as to displace'thehot air v v which would otherwise tend to .accumulate at this point. In installations of this character, the blower need not belocated above the iioor i0, but with substantially equal convenience may be located beneath the door l0 in a sealedenclosure., Invthis way, the blower would not rebutshculdnot be so great as to cause noticeable Il objectional drafts. Ordinarily, a blower having a volumetric capacity of 100 cubicv feet per minute will be found satisfactory. In a typical installation of the character disclosed herein, particularly the arrangement shown in Fig. 1. I have found that with an outside temperature of 34 F. ten minutes after the heater was started (without starting the blower 20), temperature near the top of the passenger compartment rose to 71, whereas, that at the fioor was raised only to 56. With the air about the heads of the occupants of the vehicle at 71 F., the occupants felt uncomfortably warm, and breathing became uncomfortable, while their feet were cold. Thereafter, the switch 24 w'as closed to initiate the operation of the blower 20, whereupon, after about ve minutes of operation under these conditions, the temperatureat th top 'of the compartment was raised to 79, and the temperature adjacent the iioor was raised to 78. After operation for some time under these conditions, the switch 24 was opened and after a few minutes, the temperature at the top of the compartment rose to 88, whereas, the temperature adjacent the oor dropped to V56. Repetition of these tests indicated that Without operating theblower 20, vthere is an average difference of approximately 23 between the top and floor of the passenger compartment, and under these condi.V tions, the air beneath the top' becomes stifling so as to make it undesirable to supply additional heat in an endeavor to raise the temperature of the. airV adjacent the oor. When the blower -20 .is in operation, the average difference between the temperature of the roof and that of the floor of the compartment is 7, and under these conditions even though the temperature of the air at the top is higher than when' the blower is not in operation, there is no stifling effect, undoubtedly due to the fact that the air at the top of the compartment is not stagnant, but is continually circulating about the heads of the passengers. A

From a consideration of various modicatlons of my invention disclosed herein, it will be apparent-to those skilled in the art that numerous other modifications and variations of the invention may be made without departing from the underlying principles of my invention. I thereforedesire to include withinthe scope of the following claims all such similar methods and vsuch similar constructions whereby substantially the same results may be obtained by substantially the samefmeans.

I claim: Y 1. The method of heating the passenger compartment of a sedan type automobile which comprises heating air drawn from the forward end of said compartment and discharging the heatedn air downwardly, permitting heated air to flow to the top of the vehicle by convection and displacing said heated air from the space adjacent the' top of the vvehicle by directing thereto land admixing therewith relatively cooler air drawn from the space between the front and rear seats of the vehicle adjacent the floor thereof.

2. The method of heating a closed passenger vehicle compartment provided with a transverse substantially vertical wall which interferes materially with the free circulation of air between the 'two portions of the compartment which comprises, heating the air in one portion of said lll compartment and permitting heated air to flow y by convection toward the second portion of the said compartment into the space adjacent the top of said compartmenavdrawing relatively cool air from the space adjacent the bottom of said second-portionof said compartment, and ejecting the air thus withdrawn upwardly in a forceful stream so as to cause said air to admix with and displace the warm air supplied by said heater.v

'3. In a system for heating the passenger com-A partment. of a sedan type automobile having backs for the front seats which substantlallyobstruct free circula-tion of air along the lower portion of the compartment comprising, a heater located in the portion of the compartment forwardly of the front seat and supplying heat sufcient to raise all of the air in said compartment to a comfortable temperature, a conduit having an inlet positioned adjacent the floor of the vehicle at a point between the back of the front seat and the rear seat and having an outlet adjacentthe top of the compartment, and means l for causing circulation of air through said con- 

